Called a local camera shop that carries some used equipment, in search of a Minolta fisheye that would ultimately be compatible with a future alpha purchase. It's been quite a while since I've been in there, but they used to carry quite a few used Minolta lenses. However, when I called and asked about it this time, they said that they stopped carrying them when Minolta stopped making them. I was also told that although these lenses fit Sony alphas, they don't work well with them - 'read some reviews' I was told. The purported reason they don't work well is that they're not designed for digital use, and the backsides of the lenses are coated, resulting in problems with reflections.

Given what I've read here, that this is the first I've heard of this issue, and that this shop specializes in Canon digital, I'm guessing it's just not true.

If there was a problem, you would have heard of it more widely by now. But Minolta lenses are still highly desired for use on current Sony cameras. Look at the used prices, they're holding quite high. Would they be doing that if they were so bad?

While it is true older lenses (from anyone, not just Minolta) wont have the digital coating, I'm not sure how much of a difference it really makes. At least I've not had any problems in that respect with my Tamron 28-300 dating from before the digital days.

Good thing Dyxum works on my PC (I wouldn't want to miss that site). I searched for Minolta fisheye's and found 1 result:
Minolta AF 16 F2.8 FishEye (1986)

Here are the copied reviews, positives and negatives:

positive: Sharpness, Build quality, FIlter included, Picture quality
negative: Front soft cap
comment: With film it's definitively my most favourite landscape panorama lens; nice and much wider alternatice to the Minolta 20mm; cannot touch Leicas distorsion quality, but definitely beats the Voigtlander 15mm lens; I like it not to be a circular Fisheye giving you the most out of a 1.5 cropped DSLR. Was a stunning lens in a caving tour!

positive: Sharp, even wide open, fast autofocus, focuses really close. Is the widest line I have
negative: Not wide enough on APS-C sensor, but that is not the lens' fault
comment: This is my underwater workhorse for wide angle shots. It gives excellent results. It's small, fast and accurate.
On land it is very nice to play around with, giving images with strange perspectives or nice landscapes with amazing skies.
Only minor point is that it gives around 110 degrees field of vision on APS-C sensor (it's 180 on a full frame).

positive: Only OEM AF fisheye lens
Built-in filters
Very sharp and 180 degree on film
negative: Fisheye effect disappear on cropped DSLR and angle of coverage is less
Some CA at F2.8-F4
comment: This is a very interesting lens on film but has less fisheye effect on APS-c DSLR. I like the fisheye effect for creative photography but I have to use my film camera to achieve the results. There is no true 180 degree fisheye lens for KM/Sony APS-c DSLR and the only 3rd party option Tokina 10-17 is not available in KM/Sony mount Will have to wait for the flagship full frame model from Sony.

positive: Ultra wide angle on film camera. Original perspective.
Very close focussing possible. Build in filters.
Very neutral (Minolta) colours.
negative: Effect far less on 7D because of crop factor. No front cap.
comment: For the sake of this lens alone it would be very nice if the next Alpha would be full frame. It just gives you very good quality, from corner to corner, weird perspective photos. Just be careful not to include your own feet.

positive: Unique in the Minolta line-up
Sharp from f4
Great build quality
Excellent with film but also v.good with digital
negative: Nothing that comes to mind
comment: It is a lens that I have not used often enough to justify keeping, but its very suitable for someone who likes the occasional "bendy" shot. Distortions with digital can be corrected with some processing programs or plug-ins.

positive: Sharp, contrasty and great effects.
negative: Exposed front element
comment: I purchased this lens about 5 years back and used it extensively on my film bodies and it is brilliant. The 'bendy' effects that are created are fantastic. Keeping the horrizon arcoss the centre of the frame minimizes the distortion, but tilt the lens up or down and the 'bananna' world of the fish eye emerges.
I've used this lens on my 7D, but looses its special appeal when the outside of the frame is cropped off.
The built in correction filters work well and the lens is very sharp, even in the corners, which is unusual for this type of lens.
If you already have this lens then you know all of this, but don't rush out and buy one to use on a APS-C sized sensor because it's designed for full frame and will only dissapoint.

positive: Make you look at things in a different way, sharp great colors, bendy and fast AF
negative: Bendy, no filter thread, risk to damage front glass
comment: Sharp, fast and fun to use.
Needs some thought when using it.
This is a lens that can be used in very creativ ways.

positive: A fun, well-made lens. Close-focus of 0.2m.
negative: Specialised usage. Vulnerable, bulging front element.
comment: If you're adventurous, like wide-angle shots and have a few quid to spare then this is a super lens to invest in.
At first you may find yourself merely having a right old laugh making candid photos of people's noses and other nameless body parts, each shot more grotesquely distorted than the last. But pretty soon the hilarity of that wears off. Once you compose yourself and get down to what this lens is about - making unique photos - you'll not be disappointed.
One of the best assets of the 16/2.8 in my opinion is its ability to focus very close, enabling you to place a macro subject within its environment; a leaf in a woodland, a candle in a church. The effect is unique.
I see the distortion as an asset, not a failing. If you don't want a bendy look, get a normal wide-angle.

positive: Super sharp lens with a lot of colour on it
negative: Unable to get satisfactory on 7D or 5D
comment: Never been thought a fisheye lens can be so sharp and so contrasty

positive: cool, odd, brilliant as a close-up lens that shows lots of the setting that you are in, very environmental
negative: you can't photograph anything with straight lines. (No filter thread)
comment: Solid build, really clever front lens cap.
Its very sharp. And as long as your subject is odd or certainly curved and close to you then its a really good fun lens. Takes some thought not to just produce gimicky images. But not really that hard to get keepers from it.
DO NOT BUY THIS LENS EXPECTING TO GET A 24mm ON YOUR DIGITAL BODY. It is NOT a 16>24mm convert. Its a fish-eye. Its all bendy.
Oh, it has built in filters: orange (for b&w film), FL (for shooting colour film in florescent light), blue (for shooting colour film in tungsten light) - they are no use at all for digital, I tried the orange - has no effect when converting to b&w in PhotoShop
edit - 06-Apr-07:
I've upgraded my flare control rating from 4 to 5 ... cosidering the hood design and the view, the flare control is exceptional. I've also upped the distoration from 2 to 3 - yeah its distorting, but I think that is the whole idea?
I'm soooooo totally impressed with this lens, I find it very difficult to want to shoot with anything else. I've just yesterday (05-Apr-07) gone and eBayed a Sony version to replace the Minolta one. I want the bigger focus grip and I seem to just totally get on with this lens, I simply had to go Sony with it. I'll report bak on the Sony one in a few weeks when it arrives.

positive: Amazing field of view on 35mm still about 90degrees on the 7D.
Sharp. Has built in filters. Fast focusing and bright. Nice protective material "lens cap".
negative: Can't use protective or creative filters, there is no filter thread. The built in filters are designed with film in mind. Not a big loss as often a PL filter is not suitable with such a wide FOV.
The distortion is not always a bad thing and is sometime not that noticable on the 7D. Distortion should get 5/5 for a fisheye, but 0/5 comparing it with a rectilinear lens.
comment: So wide on film you could do with a tripod with a overhang, its very easy to get the tripod legs (or your feet) in the shot! On the 7D it might even have a more useful if less impressive FOV. The sharpness is probably partly due to the large depth of field. It gets a lot more use than I thought it would.
Flare control is amazing which is good as the sun is often going to be in the shot with such a wide FOV.

comment: I have been using a Minolta AF fish-eye for about 4 years ; I found it in a second hand trade at low cost. The angle was 180° in diagonal on my Dynax 7. Now, I use it as a wide angle on my Dynax 7D, but as no specific super wide angle lens is on the market at the moment for the 7D, I have no choice ! Even a 17mm is equivalent to a 25.5 for 35mm films, so with a narrower angle than a 24 ! My estimations are that the angle of the 16mm mounted on a Dynax 7D is equivalent to a 20mm in 35mm film, so a 13mm in digital.
The big point is the residual distorsion, about 10% (compared to 17% in 35mm), but there are a lot of photo retouching softwares including distorsion correction, so I can obtain very nice pictures without any distorsion. The one I use is Photofiltre, a very good freeware available in dozens of different languages. I send you 2 pictures taken with the 16mm Minolta AF FishEye on the Dynax7D, before and after correction.

positive: Great for distorted views .
negative: With digital the crop factor on the asp-c sensor looses the lens' effect.
Can only use built in filters .
comment: This lens is a delight to use . It is sharp crystal clear with a nice color set to it. If you want a different perspective or to emphasize some thing this is the lens to use. Hard to rate the distortion considering it is a fish eye lens.

Called a local camera shop that carries some used equipment, in search of a Minolta fisheye that would ultimately be compatible with a future alpha purchase. It's been quite a while since I've been in there, but they used to carry quite a few used Minolta lenses. However, when I called and asked about it this time, they said that they stopped carrying them when Minolta stopped making them. I was also told that although these lenses fit Sony alphas, they don't work well with them - 'read some reviews' I was told. The purported reason they don't work well is that they're not designed for digital use, and the backsides of the lenses are coated, resulting in problems with reflections.

Given what I've read here, that this is the first I've heard of this issue, and that this shop specializes in Canon digital, I'm guessing it's just not true.

Anyone care to comment?

I own three Minolta AF lenses: 28-85/3.5-4.5 soom, 50mm/1.7 prime, and 50mm/2.8 Macro lens. All work very well on my Sony A200 and take excellent pictures, and I have not ever had any problems with "reflections" or digital compartibility. I don't know really who created this myth..